Grease gun

ABSTRACT

A grease gun includes a housing, a motor positioned within the housing, a pump assembly coupled to and driven by the motor, and a chamber supported by the housing in fluid communication with the pump assembly. The chamber is configured to store a liquid. The grease gun also includes an outlet in fluid communication with the chamber and a measurement system operable to measure an amount of liquid being dispensed through the outlet. The measurement system monitors a change in current of the motor over a cycle of the pump assembly, compares the change in current to a predetermined value, and, if the change in current is greater than the predetermined value, increases a pump cycle counter to indicate that liquid was dispensed.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.13/572,085, filed Aug. 10, 2012, which claims priority to U.S.Provisional Patent Application No. 61/521,903, filed Aug. 10, 2011, toU.S. Provisional Patent Application No. 61/521,987, filed Aug. 10, 2011,to U.S. Provisional Patent Application No. 61/612,835, filed Mar. 19,2012, to U.S. Provisional Patent Application No. 61/612,846, filed Mar.19, 2012, and to U.S. Provisional Patent Application No. 61/613,888,filed Mar. 21, 2012, the entire contents of all of which are herebyincorporated by reference.

This application is related to U.S. patent application Ser. No.13/571,816, filed Aug. 10, 2012, by Troy C. Thorson et al., and titled“GREASE GUN,” the entire contents of which is also hereby incorporatedby reference.

FIELD

The present invention relates to grease guns and, more particularly, togrease guns including lubricant measurement systems.

BACKGROUND

Grease guns are commonly used in workshops, industry, and garages toapply lubricant (e.g., grease) to specific points on a piece ofmachinery. Grease guns typically include a coupler positioned on the endof a hose that can be fitted to grease fittings or zerks, which in turnprovide fluid access to specific joints, gears, and other importantparts of a machine. The grease gun then pumps lubricant into thesepoints by way of a manual or powered pump.

SUMMARY

In one independent embodiment, the invention may generally provide agrease gun including a housing, a motor positioned within the housing, apump assembly coupled to and driven by the motor, and a chambersupported by the housing in fluid communication with the pump assembly.The chamber is configured to store a liquid. The grease gun may alsoinclude an outlet in fluid communication with the chamber and ameasurement system operable to measure an amount of liquid beingdispensed through the outlet. The measurement system may monitor achange in current of the motor over a cycle of the pump assembly,compare the change in current to a predetermined value, and, if thechange in current is greater than the predetermined value, increase apump cycle counter to indicate that liquid was dispensed.

In another independent embodiment, the invention may generally provide amethod of operating a grease gun. The grease gun may include a motor, apump assembly coupled to the motor, a chamber in fluid communicationwith the pump assembly and configured to store a liquid, and an outletin fluid communication with the chamber. The method may include drivingthe pump assembly with the motor to dispense liquid from the chamberthrough the outlet, monitoring a change in current of the motor over acycle of the pump assembly, comparing the change in current of the motorto a predetermined value, and increasing a pump cycle counter, if thechange in current is greater than the predetermined value, to indicatethat liquid was dispensed.

Other independent aspects of the invention will become apparent byconsideration of the detailed description, claims and accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a grease gun embodying aspects of theinvention.

FIG. 2 is an enlarged view of a control panel on the grease gun shown inFIG. 1.

FIG. 3 is a flowchart depicting operation of a lubricant measurementsystem of the grease gun.

FIG. 4 is a perspective view of another grease gun embodying aspects ofthe invention.

FIG. 5 is a perspective view of a portion of the grease gun shown inFIG. 4 with a housing portion removed.

FIG. 6 is an enlarged view of another portion of the grease gun shown inFIG. 4.

FIG. 7 is a cross-sectional view of the portion of the grease gun shownin FIG. 6.

DETAILED DESCRIPTION

Before any independent embodiments of the invention are explained indetail, it is to be understood that the invention is not limited in itsapplication to the details of construction and the arrangement ofcomponents set forth in the following description or illustrated in thefollowing drawings. The invention is capable of other independentembodiments and of being practiced or of being carried out in variousways.

FIG. 1 illustrates an electrically-powered grease gun 10. Theillustrated grease gun 10 includes a housing 14, a motor 18 supported byand positioned within the housing 14, a pump assembly 22 coupled to anddriven by the motor 18, a chamber 26 supported by the housing 14 influid communication with the pump assembly 22, and an output hose 30 influid communication with the chamber 26. In the illustrated embodiment,the chamber 26 is a barrel assembly that is configured to receive alubricant cartridge. In other embodiments, the chamber 26 may beconfigured to directly receive and store a liquid, rather than acartridge containing a liquid. In addition, the illustrated output hose30 is a flexible hose that includes an outlet and is operable todispense lubricant (or other liquids) from the chamber 26. In otherembodiments, the output hose 30 may be a rigid hose having an outlet, orthe output hose 30 may be omitted such that the outlet is directlyformed on the housing 14 to dispense lubricant.

The illustrated motor 18 is powered by a power tool battery pack suchas, for example, an 18V Li-ion battery pack. In other embodiments, themotor 18 may be powered by a battery pack having a different voltageand/or chemistry, or the grease gun 10 may be a corded power tool thatis powered by an AC power source. In operation, the motor 18 drives thepump assembly 22 to pump lubricant from a lubricant cartridge positionedwithin the barrel assembly 26. The lubricant is pumped through theoutput hose 30 and dispensed from the grease gun 10 through a fitting,or other outlet, on the end of the hose 30.

FIG. 2 illustrates a control panel 34 mounted on the grease gun 10. Theillustrated control panel 34 is a separate unit that is permanently orremovably coupled to the housing 14 of the grease gun 10. In otherembodiments, the control panel 34 may be integrated into the housing 14such that the entire grease gun assembly is a single unit.

The control panel 34 controls a lubricant measurement system of thegrease gun 10, which may include a processor and a memory. In theillustrated embodiment, the lubricant measurement system monitors motorcurrent during a pump cycle of the pump assembly 22 to determine theamount of lubricant (e.g., grease) being pumped and dispensed from thegrease gun 10 through the output hose 30. In particular, the lubricantmeasurement system monitors the current being drawn by the motor 18 todetermine the number of pump strokes performed by the pump assembly 22that actually pump lubricant. In some embodiments, the number of pumpstrokes may then converted into a volume or weight of lubricant beingdispensed by the gun 10. The lubricant measurement system can also countthe number of strokes at both a high operating speed and a low operatingspeed of the motor 18. In other embodiments, the lubricant measurementsystem may count the number of pump strokes directly to determine theamount of lubricant being dispensed.

In the illustrated embodiment, the control panel 34 includes an LCDscreen 38 and four manually operable actuators, or buttons, 42, 46, 50,54. In other embodiments, the control panel 34 may include differenttypes of display screens or actuators such as, for example, an LEDscreen and/or dials or switches. The illustrated screen 38 alternatelydisplays a “Run” page and a “Stop” page. The “Run” page shows the amountof lubricant that has already been pumped and dispensed by the greasegun 10. The “Stop” page allows a user to set the amount of lubricant tobe pumped and dispensed by the gun 10. Actuating (e.g., depressing) thefirst button 42 switches between these pages. Actuating the second andthird buttons 46, 50 adjusts the values on each page. Actuating thefourth button changes the units displayed on the screen 38. For example,the screen 38 can display the amount of lubricant already pumped or tobe pumped in ounces, grams, or number of pump strokes. In suchembodiments, the control panel 34 automatically converts the number ofpump strokes counted or to be counted by the lubricant measurementsystem into a volume or weight of lubricant already dispensed or to bedispensed. In other embodiments, the screen 38 may display the amount oflubricant already pumped or to be pumped in other units. In someembodiments, the control panel 34 may display maximum values of 15.88ounces, 450.0 grams, or 794 pump strokes. Additionally or alternatively,the control panel 34 may also include a reset button to reset (e.g.,zero) the volume, weight, and/or number of pump strokes currentlydisplayed on the screen 38.

FIG. 3 is a flowchart 100 depicting operation of the lubricantmeasurement system of the grease gun 10. When the grease gun 10 isoperated (e.g., when a trigger or other suitable actuator is actuated toenergize the motor 18 and drive the pump assembly 22), the processor andthe memory of the lubricant measurement system continuously collect andstore operating characteristics (e.g., current draw) of the motor 18. Asoperation of the grease gun 10 proceeds, a Hall sensor, or othersuitable sensor, of the lubricant measurement system is triggered by amagnet at step 104. The Hall sensor is positioned in the housing 14(FIG. 1) and coupled to the pump assembly 22 to monitor movement (e.g.,pump strokes) of the pump assembly 22. The Hall sensor is alsoelectrically coupled in communication with the processor of thelubricant measurement system. Triggering the Hall sensor indicates thatone pump cycle is completed. The processor correlates the stored currentdraw of the motor 18 over this time period (e.g., the time since theHall sensor was last triggered) with the pump cycle identified by theHall sensor.

At step 108, the lubricant measurement system checks if the change incurrent of the motor 18 (e.g., Imax of the motor 18 minus Imin of themotor 18) over the pump cycle is greater than a predetermined value. Inthe illustrated embodiment, the lubricant measurement system checks ifthe change in current is greater than approximately 0.5 amps. Thispredetermined value indicates whether the grease gun 10 actually pumpedlubricant during the measured pump cycle. Changes in current that aresmaller than 0.5 amps may occur when, for example, an air bubble is inthe pump assembly 22 or the lubricant cartridge in the barrel assembly26 is empty. In other embodiments, the predetermined value may be set ata larger or smaller value than 0.5 amps, depending on the configurationof the grease gun 10 and the type of components (e.g., motor, pumpassembly, lubricant, etc.) being used.

If the change in current is greater than the predetermined value, thelubricant measurement system increases a pump cycle counter by 1 at step112. If the change in current is not greater than the predeterminedvalue, the lubricant measurement system does not increase the pump cyclecounter such that the pump cycle counter is held or maintained at itsprevious value. After either scenario, the lubricant measurement systemcontinues to monitor the motor current at step 116 until the Hall sensoris triggered again at step 104. By not increasing the pump cycle counterwhen the change in current is less than the predetermined value, thelubricant measurement system compensates for pump strokes that do notactually pump and dispense lubricant from the grease gun 10.

After the pump cycle counter is increased, the lubricant measurementsystem compares the pump cycle counter to a preset count at step 120. Inthe embodiment shown in FIG. 2, the preset count is programmed by a userwith the control panel 34. As noted above, the user may set the presetcount as a volume of lubricant to be dispensed, a weight of lubricant tobe dispensed, or a number of pump strokes to be performed by the pumpassembly 22. If the pump cycle counter is greater than or equal to thepreset count, the lubricant measurement system stops the motor 18 atstep 124 to stop dispensing lubricant from the grease gun 10. If thepump cycle counter is not greater than or equal to the preset count(i.e., if the pump cycle counter is less than the preset count), thelubricant measurement system continues to monitor the motor current atstep 116 until the Hall sensor is triggered again at step 104.

In some embodiments, the grease gun 10 may include means to compensatefor cylinder blow past lubricant by simultaneously measuring the numberof pump strokes and an output pressure of the lubricant. The outputpressure may be measured directly or may be inferred from the motorcurrent measurement. If the measured output pressure is greater than apredetermined threshold value, the grease gun 10 may provide anindication to the user and/or shutoff power to the motor 18. Monitoringthe output pressure may also help prevent damage to gears of the motor18 or the pump assembly 22 and to the output hose 30 if the hose 30becomes blocked.

In some embodiments, the grease gun 10 may include means to remotelyactuate the gun 10 from either an end of a hose proximate a locationbeing lubricated or from a tool handle. The means may include a remotetrigger having a light. The means may also include a small plug, a smallplug inside a shutter, or another optical part positioned on the greasegun 10. The plug could be attached to the grease gun 10 after the outputhose 30 is connected to the gun 10.

FIGS. 4 and 5 illustrate another embodiment of an electrically-poweredgrease gun 110. Similar to the grease gun 10 discussed above, theillustrated grease gun 110 includes a housing 114, a motor 118 supportedby and positioned within the housing 114, a pump assembly 122 coupled toand driven by the motor 118, and a chamber 126 supported by the housing115 in fluid communication with the pump assembly 122. The housing 114includes a battery connection portion 130 configured to support abattery pack and connect the battery pack to the motor 118. Although notshown, the grease gun 110 may also include an output hose having anoutlet in fluid communication with the chamber 126.

The grease gun 110 further includes a lubricant measurement system thatdetermines the amount of lubricant (e.g., grease) being pumped anddispensed from the grease gun 110 during operation. The lubricantmeasurement system functions in a similar manner to the lubricantmeasurement system described above with reference to FIGS. 2 and 3, butincludes a manual actuator 134 rather than the control panel 34 tocontrol the system. In the illustrated embodiment, the manual actuator134 includes a rotatable dial. In other embodiments, the manual actuator134 may include a knob, a switch, a lever, or any other suitableactuator that can be manipulated by a user.

As shown in FIG. 4, the illustrated dial 134 is supported by the housing114 near a handle portion 138 and a trigger 142 of the grease gun 110.The dial 134 is positioned mostly within the housing 114, but arelatively small portion of the dial 134 extends outwardly through anopening in the housing 114 such that the dial 134 is accessible by auser. A series of values that represent numbers of pump strokes to beperformed is listed on the outer surface of the dial 134. An indicator146 is formed on the housing 114 adjacent the portion of the dial 134that extends through the housing 114. The indicator 146 identifies for auser the current setting of the dial 134.

As shown in FIGS. 5-7, the dial 134 is coupled to a circuit board 150,which includes the processor and the memory of the lubricant measurementsystem. The circuit board 150 is mounted within a forward end portion ofthe housing 114, and the dial 134 is rotatably mounted on a boss 154extending from the circuit board. By rotating the dial 134, a user canset the number of pump strokes that will be performed by the grease gun110 when the trigger 142 is actuated. For example, the dial 134 may beset such that the grease gun 110 performs 1, 2, 3, 4, 5, 6, 7, 8, 9, 10,15, 20, 25, or 50 pump strokes when the trigger 142 is actuated. Thenumber of pump strokes to be performed is identified by thecorresponding values on the dial 134. When the set number of pumpstrokes is reached, the motor 118 automatically shuts down so that thepump assembly 122 does not continue to operate and dispense lubricantfrom the grease gun 110. In other embodiments, additional or alternativenumbers of pump strokes may be available using the dial 134. In theillustrated embodiment, the dial 134 also includes an ON setting. Inthis setting, the motor 118 and the pump assembly 122 operatecontinuously until the trigger 142 is released.

Although the invention has been described in detail with reference tocertain preferred embodiments, variations and modifications exist withinthe scope and spirit of one or more independent aspects of the inventionas described. For example, although the fluid measurement system hasbeen described with reference to a grease gun, the fluid measurementsystem may also be employed with other types of motorized fluiddispensers, such as caulk guns, soap or cleaner dispensers, paintsprayers or dispensers, or the like. Furthermore, these dispensers maybe used to dispense other types of liquids (e.g., caulk, soap, paint,etc.) instead of a lubricant.

One or more independent features and advantages of the invention may beset forth in the following claims:

1. A grease gun comprising: a housing; a motor positioned within thehousing; a pump assembly coupled to and driven by the motor; a firstactuator supported by the housing and electrically coupled to the motor,the first actuator being actuatable to energize the motor; a chambersupported by the housing and in fluid communication with the pumpassembly, the chamber being configured to store a liquid; an outlet influid communication with the chamber; and a measurement systemelectrically coupled to the motor and including a second actuator, thesecond actuator being actuatable to input a number of pump strokes to beperformed, the measurement system being operable to increase a pumpcycle counter each time the pump assembly performs a pump stroke anddispenses liquid, and to automatically stop the motor when the pumpcycle counter equals the inputted number of pump strokes to beperformed.
 2. The grease gun of claim 1, wherein the measurement systemis configured to automatically stop the motor while the first trigger isactuated.
 3. The grease gun of claim 1, wherein the second actuatorincludes a dial, the dial being rotatable to input the number of pumpstrokes to be performed.
 4. The grease gun of claim 3, wherein at leasta portion of the dial extends outwardly through an opening in thehousing.
 5. The grease gun of claim 3, wherein the dial includes aplurality of values on an outer surface of the dial, each valuecorresponding to a different number of pump strokes to be performed. 6.The grease gun of claim 1, wherein the first actuator includes atrigger.
 7. The grease gun of claim 1, wherein the measurement system isoperable to monitor a change in current of the motor over a cycle of thepump assembly, to compare the change in current to a predeterminedvalue, and, if the change in current is greater than the predeterminedvalue, to increase the pump cycle counter to indicate that liquid wasdispensed.
 8. The grease gun of claim 7, wherein the measurement systemis operable to not increase the pump cycle counter if the change incurrent is less than a predetermined value.
 9. The grease gun of claim7, wherein the predetermined value is approximately 0.5 amps.
 10. Thegrease gun of claim 1, wherein the chamber includes a barrel assemblyconfigured to receive a lubricant cartridge.
 11. The grease gun of claim1, further comprising an output hose coupled to the housing and in fluidcommunication with the chamber, the output house including the outlet.12. A method of operating a grease gun, the grease gun including amotor, a pump assembly coupled to the motor, an actuator electricallycoupled to the motor, a chamber in fluid communication with the pumpassembly and configured to store a liquid, an outlet in fluidcommunication with the chamber, and a measurement system electricallycoupled to the motor, the method comprising: inputting a number of pumpstrokes to be performed into the measurement system; actuating theactuator to energize the motor; driving the pump assembly with the motorwhile the actuator is actuated; increasing a pump cycle counter of themeasurement system each time the pump assembly performs a pump strokeand dispenses liquid; and automatically stopping the motor when the pumpcycle counter equals the inputted number of pump strokes to beperformed.
 13. The method of claim 12, wherein automatically stoppingthe motor includes automatically stopping the motor while the actuatoris actuated.
 14. The method of claim 12, wherein the actuator is a firstactuator, wherein the measurement system includes a second actuator, andwherein inputting the number of pump strokes to be performed includesactuating the second actuator to input the number of pump strokes to beperformed.
 15. The method of claim 14, wherein the second actuatorincludes a dial, and wherein actuating the second actuator includesrotating the dial to input the number of pump strokes to be performed.16. The method of claim 12, wherein the actuator includes a trigger, andwherein actuating the actuator includes depressing the trigger toenergize the motor.
 17. The method of claim 12, further comprisingmonitoring a change in current of the motor over a cycle of the pumpassembly, comparing the change in current of the motor to apredetermined value, and, if the change in current is greater than thepredetermined value, increasing the pump cycle counter to indicate thatliquid was dispensed.
 18. The method of claim 17, further comprisingholding the pump cycle counter constant if the change in current is lessthan the predetermined value.
 19. The method of claim 17, wherein thepredetermined value is approximately 0.5 amps.
 20. The method of claim12, wherein inputting the number of pump strokes to be performedincludes inputting one of a volume of fluid to be dispensed and a weightof fluid to be dispensed, and wherein the method further comprisesconverting the one of the volume of fluid to be dispensed and the weightof fluid to be dispensed to the number of pump strokes to be performed.